This project consists of two parts: the synthesis of peptides of biological interest, especially those with enzymatic activity; and the modification and improvement of solid phase peptide synthesis. We are developing resin supports of improved stability and protecting groups that can be selectively removed. Several side reactions are under study and ways to eliminate them are being devised. Methods to monitor the coupling and deprotection step, especially the picric acid method, are being developed. We are using the synthetic approach to study structure-function relations in various hormones and enzymes.